Air conditioning



June 16, 1942; E. SNOOK AIR CONDITIONING Filed June 26, 1957 CONDENSER;

MAR/Ko e Win flnook Patented June 1c, 1942 I Edwin sn hum of DelawareApplication June as, 1931, 150,550 I I 2: Claims. (Gl tz-,4)

Juncoup 'i'roimwc. A

LAmarlllmTcx' assignorto Minne I I .apolis-Honcywell ompa'ny',"a' eorpoinvention relates in general to air conditioning systems. 1

The primary objectof my invention is toprovide a novel airconditioningsystem which is low in first cost and which is" dependable and highlyeconomical in-operation.

More specifically, it is anobiectyof myinvention toprovideanautomatically controlled air conditioning system of the typeutilizing a com- I pression refrigeration system in which the output ofthe compressor is'gra'duatingly varied in .trol, arrangementfis providedwhich will maintain the compressor output at the proper-yalue to carrywhatever. cooling loadis imposed up n the compressor.,- Hence, as manycooling coils as desirable may be connected toa-singlecompressor,. and,the, compressor operation will autoaccordance with the cooling or.conditioning load on the system in such manner that refrigerating effectproduced just balances the prevailing re.- quirements for refrigeration.Y

In accordance with my invention, these results are achieved ,byutilizingan internal combustion engine for driving the compressor. This type ofprime mover in its present state of development is not only verydependable and economical in operation, but also is highly flexible inoutput as its speed may easily be varied over a wide range withoutserious reduction in eiliciency. My invention contemplates utilizingthis variable speed characteristic of an internal. combustion engine forproviding a highly flexible air conditioning system which continuouslyprovides just the rematically .vary to actuate whatever coolingv coilsarein operation. I H v l A. further object of my; invention, therefore,is to provide a novel control system for a refrigeration system having-aplurality of coolin coils, the control system graduatingly.controlquired amount of air conditioning to maintain space conditionswithin proper values, and which rbadily adapts itself to any change inthe conditioning load.

In accordance with my invention, I utilize a direct expansion type ofcooling coil for cooling the air being conditioned, and control thethrottle valve or other speed controlling device for the internalcombustion engine in accordance with changes in pressure of refrigerantwithin the cooling coil By this arrangement, thespeed of the engine iscontinuously modulated in a manner to just carry the cooling load uponthe cooling coil. WhileI prefer to modulate the engine speed inaccordance with changes in the condition of the refrigerant inthecooling .coil vor evaporator, my invention is not limited to thisspecific arrangement, but may also be applied bymodulating the enginespeed in accordance with one or more conditions of the air beingconditioned.

One of the objectsof my invention, therefore, is to providean airconditioning system in which the speed of the engine or the output ofthe compressor is modulated in accordance with changes in condition ofthe air being conditioned in a'manner to provide just the necessaryrefrigeration efiect for maintaining the condition ed forstarting underload, it is necessary that ling the compressor output in a'manner tojust carry the combined cooling loads ,upon all of the cooling coils.

In utilizing an internal combustion engine for driving the compressor,provision must be made for' starting and stopping the engine. Anotherobject of the present invention consists of the provision of the enginewith automatic means for causing starting of, the engine whensthere isademand for air conditioning and for stopping the engine whenever thedemand for air conditioning disappears. 1 x v As an internal combustionengine is not adaptsuch engine be unloaded during the startingop:eration. Another object; of my invention is to provide a. novelunloading arrangement, which unloads the engine while being started andwhich automatically throws vthe load upon the engine afterithasstarted.U a

A further object of. myinventiomis the provision. ofan automatic devicefor discontinuing attempts of thecontrol apparatus to start the engineif for some reason the engine failsto start after apredetermined periodof,time.

,. Another object is the provision pr automatic control means forstopping .the en ine in the event of; failure of thesystemto operateproperly, 4 M

While my invention is concerned particularly with air conditioningsystems employing internal combustion engines, certain novel features,are

of broader application. Other objects and advantages of my inventionwill appear from the following description and the appended claims.

For a full description of my invention, reference is made to thefollowing detailed description and to the accompanying drawing in whichswitch 23.

the single figure illustrates diagrammatically one form of my invention.

portions of fresh and re-circulated air passed through the conditioningchamber. Within the inlet 4 of the conditioning chamber is an air 3filter 9 which may be of any suitable form. The air after passingthrough filter 9 flows downwardly through a direct expansion coolingcoil 2 l3 and flows from beneath said coil over a spray pipe II andthrough a heating element I2 to a fan I3 which is driven by a motor I4.The air discharged from the fan I3 is conveyed by a suitable duct I5back to the conditioned space 2. Reference character I6 indicates aby-pass damper for by-passing 'a portion of the air around the coolingcoil III. This damper is nor-- mally kept closed where the dehumidifyingload is relatively light. In locations where the dehumidifying load isheavy, however, this damper may be operated for increasingthedehumidifying effect of the coil I'll. Suitable automatic controlsfor damper I6 maybe provided if desired. The humidifying spray I I andthe heating element I2 are intended for winter operation. It will beunderstood, however, that if desired, the heating element I2 may be usedfor reheating during summer operation.

Reference characters I1 and I8 indicate suitable line wires which maybe, for instance, 110 volts A. C. These wires are connected to a doublepole switch l9 which, in turn, is connected to line wires and 2|. Theline wire 23 is connected to a wire 22 having interposed therein amanual This wire is connected to a wire 24 leading to the fan motor.Also connected to the fan motor is a wire 25, this wire being connectedto a wire 26 which, in turn, connects to the line wire 2 I. When theswitches l9 and 23 are closed, the fan motor I4 is energized for causinga flow of air through the conditioning chamber and to the space beingconditioned; During normal operation of'the system, the switches I3 and23 are kept closed and hence the fan motor I4 operatescontinuously.

Reference character 21 indicates a liquid refrigerant line leading tothe cooling coil or evaporator I3. interposed in this conduit is asolenoid valve 23 for controlling the flow of refrigerant to saidcooling coil. Reference character 29 indicates a suitable expansionvalve of known form which acts to reduce the pressure of the refrigerantentering the cooling coil I 3. This expansion valve if desired may be ofthe thermostatic type having a control bulb 33 which is attached to thedischarge or suction line 3| which conveys evaporated refrigerant fromthe cooling coil.

The solenoid'valve 28 is caused to open and close by means of athermostat 32 which is located within the conditioned space 2. Thisthermostat maybe of any suitable form and is shown herein as comprisinga circular bimetallic element 33 which carries a switch blade 34cooperating with a contact 35. When the space temperature is below apredetermined value, the bimetallic element will cause the Switch blade34 to be separated from contact 35. Upon an increase in temperature to apredetermined value, however, the switch arm 34 will be caused toengagecontact 35. Reference character 36 indicates a step-downtransformer, the primary 31 of which is connected to the wires 22 and 26thereby causing the transformer to be energized whenever the fan motorI4 is running. The sec ondary 33 of the transformer 36 has one terminalconnected to the contact 35 by a wire 33, the other terminal of saidsecondary being connected to the solenoid valve 23 by a wire 40. Theother 7 terminal of the solenoid valve 23 is connected to the bimetallicelement of the room thermostat by a wire 4|. By this arrangement, whenthe space temperature is low, the switch blade 34 of the thermostat isdisengaged from contact 35, this causing the solenoid valve 23 to bedeenergized thereby causing said valve to remain closed for preventingflow of liquid refrigerant into the cooling coil I3. When, however, thespace temperature becomes too high, the thermostat 32 will causeenergization of the valve 23 thereby causing said valveto open forpermitting flow of refrigerant into the cooling coil.

Reference character Ia indicates a second conditioning chamber forconditioning a space 2a. The conditioning chamber In may be of the sametype as the chamber I and may be provided with a solenoid valve 23acorresponding .to the valve 28 of chamber I. The valve 23a, in turn, iscontrolled by means of a thermostat 32a which is responsive to thetemperature within the space 2a. This thermostat may, likewise, controlthe solenoid valve 23a in a manner to prevent flow of refrigerant intothe cooling coil when the space temperature is low and to permit a flowof refrigerant into the cooling coil when the space temperature rises toa predetermined value.

The cooling coils of the conditioning chambers I and la are actuated bya common condensing unit, this unit consisting of a compressor 45 and acondenser 46. The discharge of the compressor 45 is connected to an oilseparator 41 by means of a conduit 43, the outlet of said oil separatorbeing connected by a conduit 43 to the refrigerant inlet of thecondenser 46. The refrigerant.

outlet of the condenser 46 is connected to a pipe 53 which leads to a Tfitting 5| to which is attached the liquid refrigerant line 21 leadingto the cooling coil I3, and'the liquid refrigerant line 21a which leadsto the cooling coil located within the chamber la. The outlet or suctionline 3| of the cooling coil I3 is connected to a T fitting 52 and thesuction line 3Ia which leads from the cooling coil within chamber Ia isalso connected to said fitting. The T fitting 52, in turn, is connectedto a main suction line 53' which is connected to the suction side of thecompressor 45.

, From the description thus far, it will be apparent that the compressor45 causes chilling of the cooling coils in both chambers I and Ia andthat the refrigerant flowing into each of said cooling coils iscontrolling by means of a thermostat responsive to the temperature ofthe space cooled by the respective cooling coil.

The compressor 45 is driven by means of an internal combustion enginegenerally indicated as 55. This internal combustion engine may be of anysuitable type and is-shown herein as arranged to utilize natural gas asa fuel. vThe engine 55 is provided with a usual intake manifold 56 towhich is attached a carburetor 51, this carburetor being connected to afuel supply pipe 58 in which is interposed a suitable pressure'reducingvalve 59. The carburetor'il isalso provided with an air intake pipe 60upon L Reference character 64 indicates a power shaft which is driven:by the engine 55. Mounted upon the'shait 64 is a'pulley 65 which drivesthrough the mediumoi belts 61 a pulley" which is mounted upon the crankshaft of the compressor 45. *By this arrangement, it'will beapparentthat the internal combustion engine I drives the compressor 45.Also mounted upon the shaft 64 is a pulley, this pulley cooperating withbelts" to drive a pulley II which, in turn, drives a wate circulatingpump I2. The purpose of pump 1 will become apparent as this descriptionproceeds.

Referring again to the engine 5, this-is cooled by means of a k 13 whichmay be open at its upper end, tank containing coil llthrough'whichcooling water may be circulated.

The water jacket outlet of the engine'is connectedto the upper end ofthetank" by means of a conduit 15, while the water Jacket inlet of theengine is-connected to the bottom of the tank by a conduit 19. By thisarrangement, the usual water circulatingpump of the enginecausescirculation of water from the engine into the top of the tank andfrom the bottom of the tank back to the engine; It will be understoodthat cooling water is circulated through coil 14 thereby causing thejacketwater tolbe cooled while flowing through't'ank 13. I v

The purpose of the pump 12 which isdriven by the engine, as. previouslydescribed, is for causing circulation of cooling water through thecondenser for condensing the refrigerant within said condenser. For thispurpose the intake of the, pump I2 is' connected to a conduit "which maylead from any suitable source of cooling water; such for instance as acooling tower which may be located upon the roof of the building beingair conditioned. The discharge of the pump "is connected to a conduit Hwhich leads to the cooling water inlet of the condenser 46.- Thecooling-water outlet of the condenser 46 is connected to a pipell! whichleads back to the cooling tower. By driving the circulating pump for thecooling water by the same prime mover 'which drives th compress'or', thesupply of cooling water to' the condenser is automatically varied inaccordance with the requirements for cooling water. Thus, when thecompressor is operating at low speed, a relatively small amount of'cooling water is neededfor condensing the compressed refrigerant. Atthis time, the circulating pump will be operating also at low speed andhenceonly'such relativelysmall quantity of cooling water 'will'besupplied. As

'the compressor speed increases, more cooling water is required. At thistime, however, the

compressor water jacket. The outlet of the compressor water jacketconnectedby a pipe 94 torthe conduit '82'.'-*Ir 1terposed"in the conduit82 between the connections "with-"pipes "and 84 is a: spring loadedreducing valve 95. The purpose orthis valve is-to'interpose 's'ufllcientresistance to the flow of waterthrough the-conduit 82 such as willcauses-flow or aportion of the water through the compressor Jacket."Located in the pipe83 is a'control valve lla'.'-' By adjusting thisvvalve, the flow of cooling water through the compressor jacket may-beregulated.

In order Ito-cool the internal combustion en'- gine'55, a pipe 96isconnected into/the water conduit II, this pipe '6 conveying cold waterfrom the cooling tower 'totheinlet. of the cool ing coil I4 which islocated within thecoolin'g tank 13 for theengine 55. The outlet of"cooling coil 14 is connected by a pipe 81 to'the conduit 92 Due to theresistance oifered by the reducing valve 95, it will be apparent thatwater will be forced from the pipe 9| through the cooling coil II to thepipe 82. Interposed in the conduit 98 is a" control valve u'flby whichthe flow of cooling water through the cooling coil 14 may be controlled.j i

Interposed between the conduits ll and 92 is a by-pass 89 having locatedtherein a valve 90. 'Ihepurpose of this by-pass is to permit a portionof the cooling'water from the cooling tower to by-pass the condenser andthe cooling through the cooling tower than flows through the condenserand cooling coil IQ, this permit ting further cooling of the coolingwater by the cooling tower. The valve 9ll'therefore provides aregulating means for controlling the'temperature of the water leavingthe cooling tower.

While I have shown the cooling tank 13 and coil I4 for indirectlycooling the engine by the condensercooling water, it will be apparentthat if desired, the condenser cooling water may be passed directlythrough the engine water jacket. In localities where the wateris-impure, however, the arrangement which I have disclosed ispreferable. 1

My invention contemplates controlling the speed of the enginegraduating'lyin accordance with the refrigeration load -upon the system.

' For this purpose, I prefer to control the throttle valve of the enginein accordance with the suction or low side pressure withintherefrigeration system. In this case, this result is achieved by theuse, of a suction pressure controller generally indicated as- 9! .whichcontrols a proportionin motor 92, this proportioning motor having anoperating arm 93 which isconnected by suitable linkage to the throttlevalve lever94 of the carburetor 51. The proportioning motor 92 may'beofany desired type and is preferably of the typeshownand described inPatent No. 2,028,110 issued to Daniel G.Taylor on January 14,1936] Thistype of proportioning motor ,is-

adapted to be controlled by means of a potentiometer and causes itsoperating shaft to assume an angular position corresponding to theposition of the potentiometer slider upon its'resistance. Motor 92receives its source of power through wires 95 and 96 which are connectedto the secondary 91 ofa step-down transformer 98.

The primary 99 of transformer 98 is connected by wireslilll and Illl tothe line wires 20 and 2|. If desired, a switch I02 may be interposed intarts and is further arranged to maintain such wire I for deenergizingtransformer 98 winter operation of the system.

The suction pressure controller 9| comprises a bellows I03, this bellowsbeing fixedly secured at its lower end and being arranged to cooperatewith the actuating arm III! of a bell-crank lever which is pivoted atI05, this bell-crank lever including a control arm I06 which cooperateswith a resistance I01 to form a control potentiometer. Thispotentiometer is connected to the proportioning motor as indicated. Theinterior of the bellows I03 is'connected to the suction line 53 by aconduit I08. Upon a rise in suction pressure, the bellows I03 willexpand, this causing movement of the control arm I00 to the left acrosscontrol resistance I01, this, in turn, resulting in a follow-up movementby the proportioning motor92 in a direction for opening the enginethrottle valve. Conversely, upon a fall in suction pressure, the bellowsI03 will contract under the action of spring I09, this causing movementof the control arm I06 in the opposite direction which results in afollow-up movement by the proportioning motor 82 in a direction to closethe engine throttle valve. The control arrangement just described,therefore, acts to increase the flow of fuel to the engine and hence toincrease the engine speed when the suction pressure increases, and todecrease the engine speed when the suction pressure decreases. Thecontroller BI may be so designed and adjusted as to maintain the suctionpressure at such a value that the cooling coil temperature is loweredsuiilciently to both cool and dehumidify the air. For instance, assumingthe Freon is used as the refrigerant, the controller 9| may be arrangedso that the control arm I06 .engagesthe right-hand end of resistance I01when the suction pressure falls to 34v pounds per square inch, and engaes the opposite end of said resistance when the suction pressure risesto 36 pounds per square inch.

My invention contemplates also the provision of automatic means forstarting the engine when cooling is required, and for stopping theengine when the demand for cooling disappears. My invention alsocontemplates the provision of safety controls for automatically placingthe engine out 'of operation whenever the system fails during .tofunction correctly. This automatic arrangement for starting and stoppingthe engine will now be described in detail. I

Reference character IIO indicates a starting relay for controlling thestarting motor 63. This relay may be of any suitable type but ispreferably of the type shown and described in Patent No, 1,773,913issued to L. K. Loehr et al. on August 26, 1930. This starting relay isSo arranged that upon' the closing of a control circuit, a magneticdevice is energized which causes pulling in of a switch in thestarter,circuit. For this purpose, the relay I I0 is connected to astoraeg battery III by means of a wire II2. Another terminal of therelay is connected to the starting motor 63 by means of a wire II3. Oneterminal of the starting motor and the battery are each grounded andhence upon the closing of the relay switch, a circuit through thestarting motor is completed. The relay H0 is also arranged to open thestarting motor circuit when the engine circuit open so long as theengine is in operation as determined by operation of the generator 62.Forth'is purpose, the generator 62 is connected to a terminal of relay II0 by a wire I I4.

For controlling the control circuit of the startvenee of a heatingelement I33.

ing relay IIO are provided a suction pressure controller II5, a highpressure cut-out H0, 9. motor temperature thermostat H1 and a thermalcut-out II8.

Referring to the suction pressure controller II5, this controller may beof any suitable form and is shown herein as comprising a bellows II!switch I22. The free end of the switch carrier" I2I is connected to aspring I23 which urges said carrier downwardly against the bellows H3.

When the suction pressure rises above a predetermined value, the bellowsII9 will expand against the action of spring. I23, this causing tiltingof the mercury switch I22 to closed position. When the suction pressurefalls, however,

the bellows II9 will contract under the action of spring I23, thiscausing tilting of the mercury switch I 22 towards open position. Thecontroller H5 is preferably of the type having a wide differential andfor this purpose the mercury switch I22 is illustrated as being of thebent type. Assuming that Freon is used as the refrigerant, thiscontroller may be so designed and adjusted that the mercury switch I22is tilted to open position when the suction pressure falls to, forinstance, 25 pounds per square inch and to tilt to closed position whenthe suction pressure rises to around 40 pounds per square inch.

Referring to the high pressure cut-out 8, this controller may be similarto the controller H5 and comprises a bellows I25 which is connected tothe compressor outlet pipe 49 by a tube I20.

The bellows I25 actuates through a suitable switch carrier a mercuryswitch I21. This controller is provided for stopping the system in theevent of failure of flow of cooling-water to the condenser and isarranged to cause opening of the mercury switch I21 whenever thepressure of the refrigerant at the compressor discharge rises above amaximum desired value, for instance, pounds per square inch (assumingthat Freon is used as the refrigerant).

The engine temperature responsive thermostat II1 comprises a bellows I28which is arranged for actuating the mercury switch I29. Bellows I28 isconnected by a capillary tube I28a to a control bulb I30 which islocated in the jacket discharge 15 of engine 55. The bulb, tube andbellows contain a suitable volatile fluid whereby the pressure withinbellows I28 varies in accordance with changes in temperature of theengine cooling water. So long as the cooling water temperature is belowa maximum, the

bellows I28 will remain contracted by a spring I3I sufliciently to holdmercury switch I23 in closed position. When, however, the enginetemperature exceeds a proper operating value, for instance 175 F., thebellows I28 will expand sufficiently to tilt mercury switch I28 to openposition.

The thermal cut-out II8 comprises a bimetallic element I32 which issubjected to the influ- Bimetallic element I32 carries a contact whichcooperates with a contact I34 for forming a switch. When the heatingelement I33 is unheated, the bimetallic element I32 will assume aposition in which the contacts are closed. When, however, the elementI33 rises to a predetermined temperature, the bimetallic element I32will warp towards the starting motor.

contact I34 whenever said element warps. sufficientlyto cause.disengagement of its contact from contact I34. Thus, wheneverheatingelement I 33 is raised to; a predetermined tempera ture,: thebimetallic element I32 will cause opening of the contacts and thecontacts will beheld open .until the, clip I35; ismanually reset.

Each of the mercury switches I22, I21 and I29 and the thermal cut-outII8 are connectedin series for controllingthe control circuit. of thestarting relay H; For thisv purposaawira-IS'I is: connected to thestorage battery, this wire leading through an ammeter I38 and a manualswitch I39 to, the mercuryswitch I29. The mercury switch I29 is, inturn, connected to mercury switch I27 by a wire- I and said latter mercuy switch-is connected by a wire I II to the mercuri switch I22, thismercury switch, in turn; being connected by a wire I42 to contact I34 ofthe thermal cut-out H8. The bimetallic, element I32 of the thermalcut-out H8 is connected by a wire I33 to the control terminal I56 of thestartin relay IIU. The wire Id3-is also connected to an ignition coil Iby means of wire I55.

-.In normal operation of the system, the mercuryswitches I29 and I21,and the thermal relay I III will remain in circuit closing position.Therefore, when the suction pressure in conduit 53 rises sufiicientlyto-cause making of mercury switch I22. the circuit from the batterythrough each of the' mercury switches and the thermal cuteout' willbeucompleted, this causing. ener- .gization of the ignition coil I45 forthe engine,

cause operation of .the starting motor for starting thewengine, andwhenthe engine is started, the relay I III will automatically deenergize theunderthe control ofthe'suction pressure controller 9! until such time asthe suction pressure in line .53 may fall sufficiently for causingcontroller' ll5'to open mercury switch I22.' This will result indeenergizing the ignition coil I45, thereby stopping the engine. j

The purposeof the startingrelay .I I8 is to deenergize the controlcircuit for the relay III) if for some reason the engineshould fail tostart within apredetermined period of time.- For this purpose, theheatingelement I33 of cut-out H8 is connected by wires I41 and llfl'tothe starting motor terminal. Theheating element-I33 is, therefore,energized wheneverthe starting motor 63 is operating; If the enginestarts normally,

the starting motor and heating element will be energized for only ashort time, and hence the heating element will not become sufllcientlyheat- Themotor will then operate j ed to cause opening of the contacts.If,-'however,

starting motor and of the ignition coil. The clip I35 will then hold thecontacts of the controller H8 inopen position thereby preventing closingof these contacts upon cooling of heating element I33. The controlarrangement just described, therefore, actsto place the system out pfoperation if the engine should fail to start.

In order to start theengine 55, it isnecessary thatthe compressorload beremovedas internal combustionengines arenot adapted for starting underload. .In order to-unload the'compressor whilethe enginev beingstarted', 1 provide an automatic clutching device whichjwill now bedescribed Reference character I50 indicates a clut'chpperating lever.This lever is arranged to be actuated by a diaphragm motor llil, thismotor including a diaphragml52 attached to (a stem I53 which, inturn, isattached to the operating lever I50. A compressionspring. I54 ,urges'the stem I53 and. the diaphragm. I52 towards the right, this causingbiasing of the clutch operating lever I50 in a manner to disengage theclutch. The diaphragm I52 is located within a-suitable housing and'suchhousing is connected by a small tube I55 to a'fitting' I56 which, inturn, is'connectedto the intake'manifold 56 by means'of a tube 'I5I.fAlso attached to the'fitting I55 a tube I58 to which is connected asolenoid valve I59. This solenoid valve is of the type which opens when'energized' and whichcloses when deenergized. One terminal of solenoidvalve I59 is grounded and the other terminal thereof is connected to thestarting motor terminal by means of wires I48 and I50.

that the engine'is at rest and the starting motor deenergized, thesolenoid valve I59 will be deenergized thereby causing it toremainclosed. At this time, also the pressurein the intake manifold ofthe engine will be equal to atmospheric pressure, and this will permitthe diaphragm I52 to be moved by spring I54 in a direction fordisengagingthe clutch. When the starting motor is energized for-startingthe engine, the solenoid valve I59 will-be caused to open. This willpermit a now 'of-air through tubes I58 and I51, which" prevents anyreduced pressure within the intake manifold from. affecting thediaphragm I52 Therefore, 'while the engine is being started, the, clutchwill be held in disengaged position by spring" I54, and the vacuumdeveloped within theintake 'inanifoldwill'fhave no effect. Aftertheengine-starts, however, thestarting motor is automatically deenerglzedand simultaneously, the solenoid valve I59 is deen'ergized therebycausing said valve to close." will prevent flow of "air into tubes I58and I51 thereby causing the pressure within said'tubes and in thehousing surroundingthe left side of the diaphragm to reduced? to "thatprevailing within the intake manifold. This will cause the diaphragm I52tobe urged'to' the left thereby causing rotation'of lever I50' forengaging the clutch. The automatic clutching mechanism Justdescribed,therefore, causes disengagement of the clutch when the engine is stoppedand causes' engagement of said clutch when the engine has started.

My invention also includes an automatic choking arrangement for chokingthe engine during the starting of operation. .For this purpose,'adiaphragm motor IGI is provided. This motor is similar to but smallerthan the clutch operating diaphragm motor previously described. Thisdiaphragm motor is arranged to actuate the choke arm I62 of thecarburetor. When the engine is at rest, the spring of the diaphragmmotor urges said motor in a direction for rotating the choke arm I52 tochoking position. After the engine is started, the vacuum developedwithin the intake manifold causes movement of the motor for rotating thechoking arm I62 to running position. Preferably, the diaphragm motor I60is arranged so as to cause movement of the choke to running positionbefore the clutch operating mechanism causes engagement of the clutch.This result may be obtained by making the spring of the choke diaphragmmotor lighter in relation to diaphragm size than the spring of theclutch operating diaphragm motor. Also, by the use of the restrictori55a the exhausting of the diaphragm chamber for the clutch operatingdiaphragm motor may be restricted, thereby causing a lapse of time tooccur before engagement of the clutch, this allowing the choke to bemoved to running position before the clutch engages. This restrictoralso acts to cause gradual engagement of the clutch.

Operation of operation.

If now'should the temperature in either space 2 or 2a become excessive,the thermostat in such space will cause opening of its respectiverefrigerant valve. This will permit flow of refrigerant into the coolingcoil in which such refrigerant evaporates for causing a cooling action.Due to this evaporation of refrigerant within the cooling coil, thesuction pressure will eventually increase to such a value that thesuction pressure controller 5' causes closing of the starting circuit,thus energizing the ignition coil for the engine and causing operationof the starting motor. At this time, the choke will be in chokingposition and the clutch will be disengaged. During the operation of thestarting motor, the solenoid valve I 59 will be held open, therebypreventing the slight vacuum in the engine occurring during the startingoperation from releasing the choke or causing engagement of the clutch.When, however, the engine starts, the starting motor is automaticallydeenergized and the solenoid valve I59 allowed to close. This closing ofthe valve I59 permits the vacuum. within the intake manifold of theengine to affect the choke diaphragm motor for releasing the choke andopening of the throttle valve. This will cause the engine speed to beincreased thereby increasing the action of the compressor forcountera'cting the increase in suction pressure. Conversely, when thetemperature of the air flowing across the cooling coil Ill decreases,less refrigerant will beevaporated, this causing the suction pressure todecrease which, in turn, results in reducing the speed of the engine.

ner to maintain aconstantsuction pressure and to vary the compressorspeed in accordance with the cooling load.

If now should the temperature in the other space become excessive, theother solenoid valve will be opened, thuspermitting a flow ofrefrigerant into the other cooling coil. The evaporation of refrigerantin this second coil will cause an increased amount of evaporated reefrigerant to flow to the compressor, this'resulting Y in the suctionpressure rising. In response to this rise in suction pressure of thesystem, the

' engine speed will increase Just sufllcientlyto be closed therebypreventing entrance of re-' 'frigerant into the cooling coils. This willpremaintain the suction pressure substantially con-- vent furtheroperation of the cooling coils thereby preventing the systemfrom-overcooling when operating. Whenever both solenoid valves areclosed, the system will automatically shut down dueto the suctionpressure being pumped down sufliciently low for causing controller I I!to break the control circuit for the internal combustion engine.

' It should be' noted that during operation of the system, thespeed ofthe water circulating pump is varied simultaneously with change in speedof the compressor, this causing the supply of cooling water for thesystem to be automatically varied in accordance with the operation ofthe system, thereby providing just the proper quantity of cooling waterfor satisfying the requirements for cooling.

then for affecting the clutch diaphragm motor for gradually engaging theclutch. Engagement of the clutch will cause operation of the compressorand will also cause operation of the water circulating pump forcirculating water to cool the condenser, the compressor, and the engine.

Operation of the compressor will cause the evaporated refrigerant to bewithdrawn from the cooling coil and compressed, this compressedrefrigerant being condensed for return to the cooling coil.

From this point, the speed of the engine will be modulated in accordancewith the cooling load upon the compressor by means of the suctionpressure controller 99. Thus, as the temperature of the air flowingacross the cooling coil increases, an increased amount of refrigerantwill be evaporated thereby causing the suction pressure of therefrigeration system to increase. In response to this increase insuction pressure, the controller 9| will cause operation of theproportioning motor 92 for increasing the From the foregoing, it will beseen that .my invention provides for automatically controlling an airconditioning system utilizing an internal combustion engine as a sourceof power. While my invention is more concerned with air conditiomngsystems utilizing internal combustion engines, certain phases of. theinvention are of broader application. Also many changes whichare withinthe scope of my invention will be apparent to those skilled in the art.I, therefore,-

said engine, means responsive to 'a load condition on the system forgraduatingly actuating said control means in a manner to vary gradu Thesuction pressure controller 9|, therefore, acts in a mansaid engine,automatic switching means in said circuit for causing starting of saidengine when air conditioning is required, automatic clutchingmechanisminterposed'between said internal combustion engine and "saidcompressor, said automatic clutching mechanism comprising a deviceresponsive to vacuum developed upon operation of said enginefor' causingengagement of said clutching mechanism, and means actuated by saidcontrol circuit for preventing operation of said vacuum responsivedevice until after said engine is started.

2. In an air conditioning system, in combination, an evaporator, meansfor causing air to be conditioned to flow in heat exchange relationshipwith said evaporator, a compressor connected to said evaporator, aninternal combustion engine for driving said compressor, control meansfor graduatingly varying the output of said engine, means responsive toa load condi-' tion' on the system for graduatingly actuating saidcontrol means in a-manner to vary graduatingly the output of said enginein accordance which changes in said load condition, a control circuitfor automatically starting and stopping said engine, automatic switchingmeans in said circuit for causing starting of said enginewhen said loadcondition, 'controlcircrii ship with said evaporator, a compressorconnected to said evaporator, an internal combustion engine for drivingsaid compressor, control means for graduatingly varying the foutput ofsaid envgine, means responsive to a load conditionon the system forg-raduatingly actuating' s'aid control means in a manner to varygraduatingly the output of said engine in accordance with'changes inautomatically starting and stoppings w hing means .associated with an '1means for starting said engine, means for unloading said engine, andcontrol means'for causing operation of said means' wh'ile said.

engine is being started and for. automatically causing said unloadingmeans to be placed out of operation after said engine has started, saidcontrol meansincluding a device controlled bysaid Y I control circuitand a device responsive to'a conditlon of the engine which varies whensaid engine stops and starts.

6. In an air conditioning system for a space,

I in combinatiomtcooling means for said space inair conditioning isrequired, and automatic clutching mechanism interposed between saidinternal combustion engine and said compressor, said automatic clutchingmechanism comprising a device responsive to vacuum developed uponoperation of said engine for causing engagement of saidclutchingmechanism.

'3. In a system of theclass described, in combination, an internalcombustion engine, means driven by. said internal combustionengine, a

control circuit for'starting and stopping said enmin an air conditioningsystem, in combina- I eluding an evaporator in heat transferrelationship with said space, a compressor connected to said evaporator,an internal combustion engine connected'to said compressor for drivingtheand means actuated by a predetermined low in-' take manifold pressureproduced by operation of the engine for rendering said unloading meanstion, anevaporaton-rmeans for causing air to be conditioned to fiow inheat exchange relaiionship with .said evaporator, a compressor connectedto said evaporator, an internal-combustion-engine for driving saidcompressor, control means for graduatingly varying the output of saidengine, means responsive to a load condition on the system forgraduatihgly actuating said control means in a manner to varygraduatingly the output of. said engine in accordance with changes insaid load condition, control circuit means for automatically startingand stopping said engine, switching means associated with saidcircuitmeans for starting said engine,- means for unloading said engine, andcontrol means for causing operation of said unloadingvmeans while saidengine is being started and for auto matically causing said unloadingmeans tobe placed out of operation after said engine has started.

5. In an air conditioning system, in combination, an evaporator, meansfor causing air to be conditioned to flow in heat exchangerelationactuating said speed controller in a manner to inoperative tothereby cause said engine to as-' sume its load after s a t g;

V 7. In an air conditioning system for a space, in combination, coolingmeans for a 81 4 including an evaporator in heat transfer relationshipwith said space, a compressor connected to said evaporator, an internalcombustion engine connected to said compressor for driving the same,said engine having a speed controller, a starting circuit means, and anintake manifold, means including a thermostat responsive tospace'tfemperature for closing 'said starting circuit meanstostartsaidengine when spacetemperature'rises 'to' apredetermined value,unloading means for permitting said engine to start in an unloadedcondition, means actuated by a predetermined low intake manifoldpressure produced-by operation ot the engine for rendering saidunloading means inoperative to thereby cause said'engin'e to assume itsload after starting, and means infiuenced by'the pressure in saidevaporator for increase the engine speedupon increase in said pressurewhile decreasing the speed upon decrease in said pressure.

, 8. In an air. conditioning assembly, a compressorhaving a dischargepipe for compressed refrigerant fluid and a suction pipe for expandedrefrigerant fluid, an internal combustion engine drivinglyconnected tosaid compressor, an ignition circuit for said internal'combustionengine, said ignition circuit including'a switch-means responsive to afunction of the operation of said compressor for controlling saidswitch, a valve in said discharge pipe, an eiectromagnet holding saidvalve in open position, said electromagnet I having an operating circuitincluding a thermostat, the construction being such that said valve 1will be held in open position by saidelectromag ans 'ior net, when thecircuit is completed through the thermostat, whereby when saidthermostat moves to open the circuit through said electromagnet saidvalve will close, altering the operation of said compressor to operatesaid switch to open said ignition'circuit.

9. In an air conditioning system for a space, in combination, coolingmeans for said space including an evaporator in heat transferrelationship with said space, a compressor connected to said evaporator,an internal combustion engine for driving said compressor, an ignitioncircuit for said engine, a speed controller for said engine, pressureresponsive means influenced by the pressure in said evaporator forpositioning said controller in a manner to increase the speed of theengine upon increase in said pressure and to decrease the speed of theengineupon decrease in said pressure, valve means for controlling theflow of refrigerant into said evaporator, means responsive to'thetemperature of said space for closing said valve means when thetemperature falls to a predetermined value, and means influenced by thepressure in said evaporator for opening said-ignition circuit inresponse to decrease in pressure in said evaporator caused by closing ofsaid valve means.

10. In an airconditioning system, in combination, a cooling coil in heatexchange relationship with the air to be conditioned, a compressorconnected to said cooling coil for withdrawing evaporated refrigeranttherefrom and for compressing such evaporated refrigerant, a condenserfor condensing the compressed refrigerant, pumping means for supplying acooling medium to said condenser, a variable speed prime mover connectedto both said compressor and said pumping means ternal combustion enginefor driving said com-- pressor, a speed controller for graduatinglyvarying the speed of said internal combustion engine, means influencedby a condition of the refrigerant which changes upon change in load onthe evaporator for controlling said speed controller in a manner foroperating the en at the proper speed for carrying the wload, ignitioncircuit for said engine, a starting mo for said engine, means includinga thermostat responsive to the temperature-of the space for energizingsaid ignition circuit upon rise in space temperature to a valuerequiring. cooling, and means energized with said ignition circuit forenergizing said starting motor for starting said engine and respondingto operation of said engine'for deenerv sizing said starting motor.

12. In an air conditioning system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, a speed controller for graduatingly varying thespeed of said internal combustion engine, means responsive to a firstcondition which is indicative of the loadon the system for controllingsaid speed controller in a. manner to graduatingly vary the engine speedin accordance with said load condition, an ignition circuit for theengine,

a starting motor for the engine, means including a device responsive toa condition of the air in said space which is afiected by saidevaporator for energizing said ignition circuit when said conditionvaries to a value indicating that conditioning of the air is desirable,and meansenergized with said ignition circuit for energizing saidstarting motor for starting said engine and responding to operation ofsaid engine for deenergizing said starting motor.

13. In an air conditioning'system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, a speed controller for graduatingly varying thespeed of said internal combustion engine, means responsive to a firstcondition which is indicative of the load on the system for controllingsaid speed controller in a manner to graduatingly vary the engine speedin accordance with said load condition, an ignition circuit for theengine, a starting motor for said engine, unloading means for saidengine, means including a device responsive to a condition of the air insaid space which is affected by said evaporator for energizing saidignition circuit when said condition varies to a value indicating thatconditioning of the air is desirable, and means energized with saidignition circuit for controlling said unloading means and said startingmotor, said last mentioned means responding to operation of said enginefor placing said starting motor and unloading means out of operation.

14. In an air conditioning system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, an ignition circuit for the engine, a startingmotor for said engine, electrical means for unloading said engine whenenergized, means including a device responsive to a condition of the airin said space which is affected by said evaporator for energizing saidignition circuit when said condition varies to a value indicating thatconditioning of the air is desirable, and means energized concurrentlywith said ignition circuit for energizing said unloading means and saidstarting motor, said last mentioned means responding to operation ofsaid engine for deenergizing said starting .motor and unloading means toplace them out of'operation.

15. In an air conditioning system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, a starting motor for said engine, loading andunloading means for said engine, said loading and unloading meansincluding electromagnetic means and being incapable of loading theengine until a lapse of time following actuation of said electromagneticmeans, switching means for controlling said starting motor and saidelectromagnetic means, and means responsive to engine operation forpositioning said switching means in a manner to place said startpressor,a starting motor for said engine, loading and unloading means for saidengine, said loading and unloading means including anelectromagnetically actuated valve said valve when open causingunloading of the engine, and being incapable of causing loading of theengine until a lapse of time following closure of said valve,

means including a device responsive to the condition of theair in saidspace which is affected by the evaporator for starting and stopping saidengine, and switching means actuated in response to engine operation forcontrolling-said starting motor and said electromagnetically actuatedvalve.

17. In an air conditioning system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, loading and unloading means for said en gine,said last recited means including an electro magnetically actuated valvearranged when open to cause unloading of the engine, said valve beingincapable of causing loading of the engine until a lapse of timefollowing closure of said valve; means including a device responsive tothe condition of the air in said space which is affected by theevaporator for starting and stopping said-'engine, and switching meansactuated in response to engine operation for controlling saidelectromagnetically actuated valve.

18. In an air conditioning system for conditioning a space, incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, a control circuit for automatically startingand stopping said engine, automatic switchautomatic clutchingmechanismfinterposed be-' tween said internal combustion engine and saidcompressor, said automatic clutching mechanism comprising a deviceresponsive to vacuum developed upon operation of the engine for causingill gine and to position said speed governing means in'its differentpositions, and means to deenergize said starter after said engine is inoperation.

20. An air conditioning system for conditioning a space, comprising, incombination, a conditioning chamber, fan means for causing air to flowthrough said chamber to said space, means including a direct expansioncooling coil for cooling the air flowing through said chamber, acompressor connected to said direct expansion cooling coil forwithdrawing evaporated refrigerant therefrom, an internal combustionengine for driving said compressor and including a fuel valve,.ignitionmeans and starting means, electrical circuits in control of the ignitionmeans and starting means of the engine, a switch in control of saidcircuits, means to render said starting means inoperative after theengine had been placed in operation and while said switch ,is closed,electrical means in control of the fuel valve of the engine energizablein a manner to position the fuel valve in at least two difierentpositions whereby the speed of the engine may be varied when the engineis in operation, and an electrical controller in control of theenergization of said electrical means, said switch and said electricalcontroller both being responsive to a single condition whichisindicative of the load on the system.

21. In a refrigeration system, in combination, an evaporator, acompressor for supplying refrigerant to said evaporator, an internalcombustion engine for driving said compressor, a starting motor fortheengine, unloading means for unloading the engine during startingthereof and including an electromagnetic valve, and means to energizesaid starting motor and valve simultaneously and to maintain said valveopen until the starting motor is deenergized, the arrangement being suchthat the load is not placed on said engine until said valve isdeenergized.

ing means in said circuit forcausing starting of the engine when airconditioning is required, and

ing the air flowing through said chamber, a compressor connected to saiddirect expansion cooling coil for withdrawing evaporated refrigeranttherefrom, an internal combustion engine including ignition means,starting means and speed governing means for driving said compressor,electrical means energizable to start said internal combustion engineand to position the speed govmeans and a circuit for the starting means,means responsive to a load condition on the system in control of saidelectrical means to start the en- 22. In a refrigeration system, incombination,

an evaporator, a compressor for supplying refrigerant to saidevaporator, an internal combustion engine for driving said compressor, astarting motor for the engine, unloading means for unloading the engineduring starting thereof and including an electromagnetic valve, means toenergize said starting motor and valvesimultaneously and to maintainsaid valve open until the starting motor is deenergized, the arrangementbeing such that the load is not placed on said engine until said valveis deenergized, and means for automatically varying the speed of saidengine in accordance with the load on the system while the engine is inoperation.

23. In an air conditioning system for conditioning a space,-incombination, an evaporator in heat exchange relationship with saidspace, a compressor connected to said evaporator for withdrawingevaporated refrigerant therefrom, an internal combustion engine fordriving said compressor, a starting motor for said engine, loading meansfor said engine, time delay means in control of said loading means, andcontrol means responsive to engine operation for automatically renderingsaid starting motor inoperative and for simultaneously placing said timedelay means in operation when the engine is in operation whereby theloadis applied to said eni gine only after a delayed interval followingdeenergization of said starting motor.

EDWIN SNOOK.

